THE BUTTERFLIES OF THE BRITISH ISLES. 



T 



CL b 



Fig. 2. 

 (a) True and (b) false legs. 



from the figure that the true legs {a) differ from the false legs (b) 

 in structure. The former are horny, jointed, and have terminal 



claws ; the latter are fleshy, 

 with sliding joints, and the foot 

 is furnished with a series of 

 minute hooks which enable the 

 caterpillar to obtain a secure 

 hold when feeding, etc. The 

 false legs are also the chief 

 means of locomotion, as the 

 true legs are of little service for this purpose. The true legs, 

 however, appear to be of use when the caterpillar is feeding, as 

 the leaf is held between them so as to keep it steady whilst 

 the jaws are doing their work. 



In the accompanying figure of the head of a caterpillar the 

 mouth parts are clearly shown. The biting jaws {mandibles) 

 are slightly apart, above them is 

 seen the upper lip {labrum\ and 

 below them is the under lip {labium 

 or lingua). The maxillce are very 

 tiny affairs, but they should be 

 noted because in the butterfly they 

 become the basal portions of the 

 two tubes which, when united to- 

 gether, form the sucking organs 

 (proboscis). The eyes, or ocelli as 

 they are termed, are minute, and 

 are said to be of slight use to the 

 caterpillar as organs of sight, so 

 that it probably has to depend on its little feelers {antenna) for 

 guidance to the right plants for its nourishment. Attention 

 should also be given to the spinneret, as it is by means of this 

 that the silken threads, etc., for its various requirements are 

 provided ; the substance itself being secreted in glands placed 



St f 



Fig. 3. 

 a, labrum ; b, mandible ; c, 

 antenna ; d, ocelli ; e, max- 

 illa ; /, labium ; g, spin- 

 neret ; h y labial palp. 



